On Tue, Mar 03, 2015 at 01:58:46PM +0530, Aneesh Kumar K.V wrote: > Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> writes: > > > Until now, reserved pages for CMA are managed altogether with normal > > page in the same zone. This approach has numorous problems and fixing > > them isn't easy. To fix this situation, ZONE_CMA is introduced in > > previous patch, but, not yet populated. This patch implement population > > of ZONE_CMA by stealing reserved pages from normal zones. This stealing > > break one uncertain assumption on zone, that is, zone isn't overlapped. > > In the early of this series, some check is inserted to every zone's span > > iterator to handle zone overlap so there would be no problem with > > this assumption break. > > > > To utilize this zone, user should use GFP_HIGHUSERMOVABLE, because > > these pages are only applicable for movable type and ZONE_CMA could > > contain highmem. > > > > Implementation itself is very easy to understand. Do steal when cma > > area is initialized and recalculate values for per zone data structure. > > > > Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> > > --- > > include/linux/gfp.h | 10 ++++++++-- > > include/linux/mm.h | 1 + > > mm/cma.c | 23 ++++++++++++++++------- > > mm/page_alloc.c | 42 +++++++++++++++++++++++++++++++++++++++--- > > 4 files changed, 64 insertions(+), 12 deletions(-) > > > > diff --git a/include/linux/gfp.h b/include/linux/gfp.h > > index 619eb20..d125440 100644 > > --- a/include/linux/gfp.h > > +++ b/include/linux/gfp.h > > @@ -186,6 +186,12 @@ static inline int gfpflags_to_migratetype(const gfp_t gfp_flags) > > #define OPT_ZONE_DMA32 ZONE_NORMAL > > #endif > > > > +#ifdef CONFIG_CMA > > +#define OPT_ZONE_CMA ZONE_CMA > > +#else > > +#define OPT_ZONE_CMA ZONE_MOVABLE > > +#endif > > + > > Does that mean with CONFIG_CMA we always try ZONE_CMA first and then > fallback to ZONE_MOVABLE ? If so won't we hit termporary CMA allocation > failures that can result with pinned movable pages ? Hello, Aneesh. IIUC, Johannes's fair allocation policy patchset makes us uses individual zones fairly. So, before freepage on ZONE_CMA is exhausted, ZONE_MOVABLE will be used. :) Thanks. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>